The present disclosure relates to a light emitting device and a light emitting device package.
A light emitting diode (LED) is a kind of a semiconductor device for converting electric energy into light. The LED has advantages such as low power consumption, a semi-permanent life cycle, a fast response time, safety, and environment friendly compared to the related art light source such as a fluorescent lamp and an incandescent bulb. Many studies are being in progress in order to replace the related art light source with an LED, and the LED is being increasingly used according to the trend as a light source of lighting equipment such as a variety of lamps, a liquid crystal display device, a scoreboard, a streetlight in indoor and outdoor places.
In the LED, a stacked light emitting structure layer includes a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, and the light is generated from the light emitting structure layer according to an applied power supply.
In the LED, an epi-layer is used to form the light emitting structure layer on a growth substrate such as a sapphire substrate, and then a reflective layer is formed on the light emitting structure layer. Moreover, after bonding of the reflective layer and a conductive support substrate, an LED having a vertical structure is manufactured through a process for removing the growth substrate.
In addition, when the growth substrate is separated through a laser beam, due to a mechanical impact and explosive power of N2 gas occurring during a thermo-chemical decomposition of a buffer layer material, crack or breaking occurs in the epi-layer.
Furthermore, in a case of Au—Sn, Au—In, Pd—In, Pd—Sn (i.e., a solder bonding material system) used for bonding the reflective layer and the conductive support substrate, materials such as Pt, W, and Cr are used as a diffusion barrier layer to prevent fast diffusion of Sn or In. At this point, in a case of Pt, a solder bonding material has an embrittlement property due to depletion of Sn or In and in a case of W and Cr, separation occurs due to a poor adhesiveness of Sn or In.